Date: Fri, 01 May 2026 16:10:18 +0000 (UTC) From: FreeBSD Errata Notices <errata-notices@freebsd.org> To: FreeBSD Errata Notices <errata-notices@freebsd.org> Subject: FreeBSD Errata Notice FreeBSD-EN-26:11.dhclient Message-ID: <20260501161018.30CED12D5F@freefall.freebsd.org>
index | next in thread | raw e-mail
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA512
=============================================================================
FreeBSD-EN-26:11.dhclient Errata Notice
The FreeBSD Project
Topic: dhclient(8) lease validation is too strict
Category: core
Module: dhclient
Announced: 2026-05-01
Affects: All supported versions of FreeBSD.
Corrected: 2026-04-30 21:07:00 UTC (stable/15, 15.0-STABLE)
2026-05-01 15:08:46 UTC (releng/15.0, 15.0-RELEASE-p8)
2026-04-30 21:07:11 UTC (stable/14, 14.4-STABLE)
2026-05-01 15:08:37 UTC (releng/14.4, 14.4-RELEASE-p4)
2026-05-01 15:08:30 UTC (releng/14.3, 14.3-RELEASE-p13)
2026-04-30 21:07:24 UTC (stable/13, 13.5-STABLE)
2026-05-01 15:08:19 UTC (releng/13.5, 13.5-RELEASE-p14)
For general information regarding FreeBSD Errata Notices and Security
Advisories, including descriptions of the fields above, security
branches, and the following sections, please visit
<URL:https://security.FreeBSD.org/>.
Note: While FreeBSD 13.5 is end of life (EOL) as of May 1st, 2026, the
Security Team has decided to patch this issue as it was identified and a fix
was in-flight before the EOL date.
I. Background
dhclient(8) is the default IPv4 DHCP client used on FreeBSD. It is
responsible for contacting DHCP servers on a network segment and for
initialising and configuring network interfaces based on received
information.
When processing a DHCP offer, dhclient passes various parameters provided by
the server to dhclient-script(8). DHCP options, as documented in
dhcp-options(5), are passed via the environment.
II. Problem Description
The patch for FreeBSD-SA-26:15.dhclient introduced some validation of the
boot file DHCP option to prevent unescaped values from being written to the
stored lease file. This validation is overly strict and rejects Windows
paths.
III. Impact
The overly strict validation may cause dhclient(8) to reject valid leases.
IV. Workaround
No workaround is available. Systems not running dhclient(8) are not
affected.
V. Solution
Upgrade your system to a supported FreeBSD stable or release / security
branch (releng) dated after the correction date.
Perform one of the following:
1) To update your system installed from base system packages:
Systems running a 15.0-RELEASE version of FreeBSD on the amd64 or arm64
platforms, which were installed using base system packages, can be updated
via the pkg(8) utility:
# pkg upgrade -r FreeBSD-base
2) To update your system installed from binary distribution sets:
Systems running a RELEASE version of FreeBSD on the amd64 or arm64 platforms,
or the i386 platform on FreeBSD 13, which were not installed using base
system packages, can be updated via the freebsd-update(8) utility:
# freebsd-update fetch
# freebsd-update install
3) To update your system via a source code patch:
The following patches have been verified to apply to the applicable
FreeBSD release branches.
a) Download the relevant patch from the location below, and verify the
detached PGP signature using your PGP utility.
# fetch https://security.FreeBSD.org/patches/EN-26:11/dhclient.patch
# fetch https://security.FreeBSD.org/patches/EN-26:11/dhclient.patch.asc
# gpg --verify dhclient.patch.asc
b) Apply the patch. Execute the following commands as root:
# cd /usr/src
# patch < /path/to/patch
c) Recompile the operating system using buildworld and installworld as
described in <URL:https://www.FreeBSD.org/handbook/makeworld.html>.
Restart the applicable daemons, or reboot the system.
VI. Correction details
This issue is corrected as of the corresponding Git commit hash in the
following stable and release branches:
Branch/path Hash Revision
- -------------------------------------------------------------------------
stable/15/ 252f603d1704 stable/15-n283453
releng/15.0/ dc8762cfb6e2 releng/15.0-n281035
stable/14/ 2f9478ad42c4 stable/14-n274094
releng/14.4/ dfcb69cdb07e releng/14.4-n273699
releng/14.3/ 5bad905eb37f releng/14.3-n271499
stable/13/ b1ece85741db stable/13-n259871
releng/13.5/ b362b6b6c8f2 releng/13.5-n259221
- -------------------------------------------------------------------------
Run the following command to see which files were modified by a
particular commit:
# git show --stat <commit hash>
Or visit the following URL, replacing NNNNNN with the hash:
<URL:https://cgit.freebsd.org/src/commit/?id=NNNNNN>;
To determine the commit count in a working tree (for comparison against
nNNNNNN in the table above), run:
# git rev-list --count --first-parent HEAD
VII. References
<URL:https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=294886>;
The latest revision of this advisory is available at
<URL:https://security.FreeBSD.org/advisories/FreeBSD-EN-26:11.dhclient.asc>;
-----BEGIN PGP SIGNATURE-----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=Ro3y
-----END PGP SIGNATURE-----
home |
help
Want to link to this message? Use this
URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20260501161018.30CED12D5F>